Touch-sensitive displays, or “touchscreens,” are used predominantly in so-called touchscreen terminals which can be operated by a user touching the screen with a finger, whereby the keyboard and mouse known from the PC are generally dispensed with.
A confirmation that an input effected by a user has actually taken place is, in general, obtained by means of audiovisual feedback; for example, by means of a beep sound or a change of color of the display area when the display is touched.
Touchscreen terminals are set up at trade fairs, presentations or in the reception areas of companies in order to enable dialog with customers. Touchscreen terminals also can be found at airports and in city centers as information terminals for tourists, and in manufacturing facilities for data entry and control purposes in production processes.
One disadvantage experienced with the above mentioned applications are loud and irregularly occurring ambient noises which occur at airports and in streets and production facilities, with the result that there is a danger of audible feedback being masked by the ambient noises and going unnoticed by the user.
Visual feedback is similarly dependent on ambient influences. For example, direct or reflected sunlight can cause irritation, with the result that the visual feedback does not achieve the desired effect. In addition, situations also occur whereby users obscure areas of the display intended for the visual feedback with their hand.
Furthermore, a touch-sensitive monitor is known from U.S. Pat. No. 4,885,565, in which tactile feedback is initiated when an input is made by a user touching the screen. To this end an oscillating coil is driven in such a way by a microprocessor that it triggers a mechanical stimulus which causes the housing of the monitor to vibrate so that the user can also feel that his/her input has been detected in addition to receiving the audiovisual feedback.
The disadvantage of this solution is that regardless of which input has been made by the user touching the screen, the same tactile feedback always occurs and a differentiation is only possible when taken in conjunction with the audiovisual feedback which is still present as before.
An object to which the present invention is directed is, therefore, to set down a touch-sensitive display with tactile feedback which resolves the disadvantages of the prior art.